diff --git a/.gitlab-ci.yml b/.gitlab-ci.yml
index cb75101d1..28ba9da66 100644
--- a/.gitlab-ci.yml
+++ b/.gitlab-ci.yml
@@ -1,11 +1,18 @@
 image: elixir:latest
 
 services:
-  - postgres:latest
+  - mdillon/postgis:9.6-alpine
 
 variables:
   MIX_ENV: "test"
 
+cache:
+  key: "$CI_JOB_NAME"
+  paths:
+    - deps
+    - _build
+    - .rebar3
+
 before_script:
   - mix local.rebar --force
   - mix local.hex --force
@@ -13,4 +20,5 @@ before_script:
 
 mix:
   script:
+  - mix credo
   - mix test
diff --git a/mix.exs b/mix.exs
index 034d642d1..adedd048f 100644
--- a/mix.exs
+++ b/mix.exs
@@ -53,6 +53,7 @@ defmodule Eventos.Mixfile do
       {:timex, "~> 3.0"},
       {:timex_ecto, "~> 3.0"},
       {:ex_machina, "~> 2.1", only: :test},
+      {:credo, "~> 0.8", only: [:dev, :test], runtime: false},
     ]
   end
 
diff --git a/mix.lock b/mix.lock
index 21e405728..9f0c0f829 100644
--- a/mix.lock
+++ b/mix.lock
@@ -1,5 +1,6 @@
 %{"argon2_elixir": {:hex, :argon2_elixir, "1.2.14", "0fc4bfbc1b7e459954987d3d2f3836befd72d63f3a355e3978f5005dd6e80816", [:make, :mix], [{:elixir_make, "~> 0.4", [hex: :elixir_make, repo: "hexpm", optional: false]}], "hexpm"},
   "base64url": {:hex, :base64url, "0.0.1", "36a90125f5948e3afd7be97662a1504b934dd5dac78451ca6e9abf85a10286be", [:rebar], [], "hexpm"},
+  "bunt": {:hex, :bunt, "0.2.0", "951c6e801e8b1d2cbe58ebbd3e616a869061ddadcc4863d0a2182541acae9a38", [], [], "hexpm"},
   "certifi": {:hex, :certifi, "2.0.0", "a0c0e475107135f76b8c1d5bc7efb33cd3815cb3cf3dea7aefdd174dabead064", [], [], "hexpm"},
   "coherence": {:hex, :coherence, "0.5.0", "aaa785aa29e47d140030502b66b08fb58ec84e8120acbfaa6e6a61d3322ffa76", [], [{:comeonin, "~> 3.0", [hex: :comeonin, repo: "hexpm", optional: false]}, {:ecto, "~> 2.0", [hex: :ecto, repo: "hexpm", optional: false]}, {:gettext, "~> 0.13", [hex: :gettext, repo: "hexpm", optional: false]}, {:phoenix, "~> 1.3", [hex: :phoenix, repo: "hexpm", optional: false]}, {:phoenix_html, "~> 2.10", [hex: :phoenix_html, repo: "hexpm", optional: false]}, {:phoenix_swoosh, "~> 0.2", [hex: :phoenix_swoosh, repo: "hexpm", optional: false]}, {:timex, "~> 3.1", [hex: :timex, repo: "hexpm", optional: false]}, {:timex_ecto, "~> 3.1", [hex: :timex_ecto, repo: "hexpm", optional: false]}, {:uuid, "~> 1.0", [hex: :uuid, repo: "hexpm", optional: false]}], "hexpm"},
   "combine": {:hex, :combine, "0.10.0", "eff8224eeb56498a2af13011d142c5e7997a80c8f5b97c499f84c841032e429f", [], [], "hexpm"},
@@ -8,6 +9,7 @@
   "cors_plug": {:hex, :cors_plug, "1.5.0", "6311ea6ac9fb78b987df52a7654136626a7a0c3b77f83da265f952a24f2fc1b0", [:mix], [{:plug, "~> 1.4", [hex: :plug, repo: "hexpm", optional: false]}], "hexpm"},
   "cowboy": {:hex, :cowboy, "1.1.2", "61ac29ea970389a88eca5a65601460162d370a70018afe6f949a29dca91f3bb0", [:rebar3], [{:cowlib, "~> 1.0.2", [hex: :cowlib, repo: "hexpm", optional: false]}, {:ranch, "~> 1.3.2", [hex: :ranch, repo: "hexpm", optional: false]}], "hexpm"},
   "cowlib": {:hex, :cowlib, "1.0.2", "9d769a1d062c9c3ac753096f868ca121e2730b9a377de23dec0f7e08b1df84ee", [:make], [], "hexpm"},
+  "credo": {:hex, :credo, "0.8.10", "261862bb7363247762e1063713bb85df2bbd84af8d8610d1272cd9c1943bba63", [], [{:bunt, "~> 0.2.0", [hex: :bunt, repo: "hexpm", optional: false]}], "hexpm"},
   "db_connection": {:hex, :db_connection, "1.1.2", "2865c2a4bae0714e2213a0ce60a1b12d76a6efba0c51fbda59c9ab8d1accc7a8", [:mix], [{:connection, "~> 1.0.2", [hex: :connection, repo: "hexpm", optional: false]}, {:poolboy, "~> 1.5", [hex: :poolboy, repo: "hexpm", optional: true]}, {:sbroker, "~> 1.0", [hex: :sbroker, repo: "hexpm", optional: true]}], "hexpm"},
   "decimal": {:hex, :decimal, "1.4.1", "ad9e501edf7322f122f7fc151cce7c2a0c9ada96f2b0155b8a09a795c2029770", [:mix], [], "hexpm"},
   "ecto": {:hex, :ecto, "2.2.7", "2074106ff4a5cd9cb2b54b12ca087c4b659ddb3f6b50be4562883c1d763fb031", [:mix], [{:db_connection, "~> 1.1", [hex: :db_connection, repo: "hexpm", optional: true]}, {:decimal, "~> 1.2", [hex: :decimal, repo: "hexpm", optional: false]}, {:mariaex, "~> 0.8.0", [hex: :mariaex, repo: "hexpm", optional: true]}, {:poison, "~> 2.2 or ~> 3.0", [hex: :poison, repo: "hexpm", optional: true]}, {:poolboy, "~> 1.5", [hex: :poolboy, repo: "hexpm", optional: false]}, {:postgrex, "~> 0.13.0", [hex: :postgrex, repo: "hexpm", optional: true]}, {:sbroker, "~> 1.0", [hex: :sbroker, repo: "hexpm", optional: true]}], "hexpm"},